Loop-taker adjusting means for sewing machines



H. RlTTER Sept. 27, 1955 LOOP-TAKER ADJUSTING MEANS FOR SEWING MACHINES Filed Aug. 28 1951 INVENTOR. Jrman Bitter WITNESS ATTORNEY i/mqw azzd my I United States Patent LOOP-TAKER ADJUSTING MEANS FOR SEWING MACHINES Herman Ritter, Cranfor'd, N. J., assignor to The Singer lvlannfacturing Company, Elizabeth, N. 1., a corporation of New Jersey Application August 28, 1951, Serial No. 243,964

4 Claims. (21. 112-181) The present invention relates to sewing machines and has for its object to provide, in a sewing machine, a means for laterally adjusting a loop-taker on its shaft and, more particularly, a loop-taker of the rotary hook type, thereby to maintain the proper clearance between the loop-seizing beak of the loop-taker and the needle.

During normal sewing operations, the beak of a rotary loop-taker becomes worn away, or scarred as by hitting a bent needle and must be repolished which also removes a portion of the beak. Although the amount worn away or removed in polishing may be very small, it may, nevertheless, be sufficient to cause skipping of stitches. To avoid this faulty operation, the loop-taker must be readjusted endwise of its shaft toward the needle, to restore the proper clearance between the beak of the loop-taker and the needle.

Heretofore, no means for readily accomplishing this readjustment has been provided and it was necessary to resort to adjustments which were inherently inaccurate and time consuming because of the minute dimensions involved, and because the loop-taker would be moved in an uncontrolled manner. By means of the device hereing set forth this adjustment can be readily and accurately made.

With the above and other objects in view, as will be evident from an understanding of this disclosure, a presently preferred embodiment of the invention is hereinafter set forth in such detail as to enable those skilled in the art to readily understand the function, operation, construction and advantages of it, when read in conjunction with the accompanying drawings, in which:

Fig. 1 is a vertical section of a rotary hook form of loop-taker embodying the features of the invention, with fragmentary portions of the associated bed mechanism of a sewing machine included.

Fig. 2 is a fragmentary view similar to Fig. 1 but showing the illustrated parts in a relatively different relation.

Fig. 3 is a plan view of the hook-body of Fig. 1 shown per se.

Fig. 4 is a perspective view of the hook of Fig. 1 shown per se.

As set forth hereinafter, the invention is disclosed as embodied in a looper-taker of the rotary-hook type. However, it is to be understood that this is only for purposes of illustration since the invention can also be applied to certain types of loopers for chain-stitch machines or oscillating hooks or shuttles as will be readily understood by those skilled in the art.

With reference to the drawings, there is shown a portion of a sewing machine bed 1 having a work-supporting surface 2 and a throat-plate 3. Integral with the bed 1 is a depending boss 4 provided with a bore 5 in which is seated a bearing bushing 6 secured therein by a screw 7 and in which bushing 6 is journaled a bed-shaft 8. Fixed to the shaft 8 by a screw 9 is a collar 10 having peripheral grooves 11 formed therein which constitute an oil sling adapted to transfer the excess of the lubrication oil sup- 2,718,858 Patented Sept. 27, 1955 plied to the surfaces between the stationary bushing 6 and rotating collar 10 to an oil groove 12 in the boss 4 connected to an oil-return duct 13.

A rotary hook 14 having a hub portion 15 provided with a bore into which the end of the shaft 8 projects is fixed to the shaft 8 by means of screws 16. Integral with the hub is a cup-shaped body member including a base-wall 17 of a discontinuous circular side wall 17 having a loop-seizing beak 18 formed upon the free rim of the wall. The rotary hook is also provided with a bobbin-carrier 19 having a peripheral bearing rib 20 journaled in a raceway in the side wall 17, and a bobbincarrier retaining gib 21.

The above structure is old and well known being illustrated for instance, in my prior U. S. Patent No. 2,529,573, issued November 14, 1950, and the details thereof form no part of the present invention. Therefore, it is not deemed necessary to expand this disclosure in relation thereto.

In accordance with the present invention, there is provided in the hub 15 a threaded bore 22 parallel to the axis thereof and located radially eccentric thereto. Adjacent that end of the hub 15 which abuts against the face of the collar 10, the bore 22 is enlarged to form a counterbore 23. A screw 24 carrying a head or plunger 25 at one end and provided with a slot 26 at the other is adapted to be threaded into the bore 22 with the head 25 thereof seated in the counterbore 23 and the slot 26 exposed through the opposite end of the bore 22. As best seen in Fig. 4, the slot 26 is also exposed through the cutaway bottom wall of the bobbin-carrier 19. The depth of the counterbore 23 is such that the shoulder between the screw 24 and plunger 25 will contact the inner wall of the counterbore before the slotted end of the screw projects beyond the inner face of the base-wall 17 adjacent the bobbin-carrier 19, to prevent that screw from interfering with the relative rotation between the loop-taker and bobbin-carrier 19.

In the usual manner, the beak 18 is adapted to seize the thread-loop cast out by a needle 27 which reciprocates through the usual needle-opening in the throatplate 3. To provide maximum insurance that the beak 18 will enter the needle-thread loop, it must pass as closely as possible to the needle without striking it. Initially, the loop-seizing beak can be readily positioned very accurately by properly locating the collar 10, since the proximate face of the hub 15 abuts directly against the collar, as seen in Fig. 1. However, in use, wear and polishing of the hook-beak results in an improper clearance between the beak 18 and needle 27. i

To reestablish the desired minimum clearance between the needle and the loop-seizing beak, it is desirable to adjust the hook relative to the shaft 8 and the collar Ill. This may now be accomplished by loosening the screws 16, whereby the hook is slidable on the shaft, and turning the screw 24, the slotted end of which can be readily engaged by a screw-driver or similar tool inserted through the bobbin-carrier after the bobbin-case has been removed. Upon turning the screw 24, the initial movements place the face of the head 25 into engagement with the collar 10 and continued turning thereof forces the head 25 outwardly from the hub face, which forces the hub and collar apart, and thus moves "the hook beak 18 towards the needle 27. By means of the screw 24, a very fine adjustment of the hook on the shaft 8 can be made. When the desired adjustment has been reached, the hook is again locked in that position by retightening in the screws 16. It should also be noted that if it becomes necessary for any reason to remove the hook from the shaft, it may readily be replaced in the adjusted position merely by moving the face of the head 25 into engagement with the collar 10.

U Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed asa limitation thereof. All such modifications which do not depart from the spirit of my invention are intended to be included within the scope of the" appended claims.

Having thus set forth the nature of the invention, what I claim herein. is:

1. A sewing machine l1oop-taker having a body-mcmber including a base-wail and a hub extending from one side of said base-wall, said hub being provided with a shaft-bore" and with a second bore lengthwise disposed substantially parallel to said: shaft bore and coextensive with said hub and base-wall, and a loop-taker adjustingscrew threaded into said second bore.

2t A sewingmachine loop-taker having a cup-shaped body including a cylindrical side wall, a base-wall, and a hub extending from said base-wall in a direction away from said cylindrical. sidewall, said hub being provided with a shaft-bore and with a counterboredsecond bore lengthwise disposed substantially parallel to said shaftbore, and an adjusting screw threaded into said second bore and having. an enlarged head disposed in the counterbore of said second bore, thereby limiting movement of said screw in one direction.

l 3. In a sewing machine, a rotary actuating shaft, a rotary loop-taker having a body provided with an axial bore entered by said shaft, releasable means for securing said loop-taker upon said shaft, a loop-taker adjusting screw threaded into said body in a direction substantially parallel to said shaft, and a collar carried by said shaft for rotation therewith and in position for engagement by said screw.

'4. In a sewing machine, a rotary loop-taker actuating shaft, a rotary loop-taker having a hub formed with a bore, manual means for releasably securing said looptaker upon said shaft with the bore in the hub of said loop-taker receiving said shaft, and means for adjusting the loop-taker lengthwise of said shaft comprising an abutment normally fixed against lengthwise motion relative to said shaft, and an adjusting screw threaded into said hub with one end normally in position to engage said abutment for limiting the amount that said shaft will extend intosaid bore in the hub of the loop-taker and its other end readily accessible for adjustment.

Nelson May 29, 1917 ,Graesser Sept. 22, 1942 

